JP3336123B2 - Pellet position detection method for pellet bonding equipment - Google Patents

Abstract

PURPOSE:To improve a pellet bonding device in accuracy of detecting the position of a pellet without making it complicated in structure CONSTITUTION:Image picture data of one corner A of a pellet 13 are latched by a camera, and the a rotary table 24 is rotated to position the other corner B of the pellet 13 in the recognition region of the camera and to enable the camera to latch the image picture data of the corner B, and the positional deviations of the corners A and B from the reference positions of them are detected on the basis of the picture image data of the corners A and B and the reference picture image data of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a pellet position in a pellet bonding apparatus.

[0002]

2. Description of the Related Art One of semiconductor manufacturing processes is a pellet bonding process using a pellet bonding apparatus. In this step, first, pellets are taken out of the wafer placed on the wafer stage by the suction nozzle of the pellet transfer constituting the pellet take-out mechanism, and the taken-out pellets are placed on the rotary table of the pellet position correcting mechanism. Next, the X, Y, θ
The state of displacement from the reference position in each direction is detected using a camera. And θ of the pellet
After the misalignment state in the direction is corrected by the rotation of the rotary table, the pellets are picked up by a suction nozzle (commonly referred to as a collet) of a bonding head constituting a bonding mechanism, conveyed to a predetermined position of a lead frame, and bonded. You. The actual pickup position by the suction nozzle of the bonding head is corrected (position correction in the X and Y directions) in accordance with the positional shift state of the pellet in the X and Y directions with respect to the pickup reference position. Even if the pellets are misaligned, the central position is picked up by the suction nozzle.

In the meantime, as shown in FIG. 3A, the position detection of the pellet by the camera is performed by positioning one corner a of the pellet 1 placed on the turntable 2 in the recognition area 3 of the camera. The shift amount from the reference position of the corner portion a and the edge line 4 of the pellet 1 are obtained from the image information captured from the area, and the position coordinates and the rotation angle of the corner portion a are detected based on these data. ing. (First conventional example).

[0004] As another method for detecting a pellet position,
As shown in FIG. 3B, the rotary table 2 is set on the XY table 5, and the XY table 5 is moved to fix one corner a of the pellet 1 and another corner b. There is a type in which the image information is fetched while being sequentially positioned in the recognition area 3 of the arranged camera, and the position of the pellet 1 is detected based on the image information of both corners a and b and each of the reference image information. (Second conventional example).

[0005]

However, in the first conventional method for detecting the position of the pellet, the recognition area 3 of the camera is not sufficient.
Is a limited area, the detection of the rotation angle of the edge line 4 in the recognition area 3 has low accuracy, and as a result,
The detection accuracy of the pellet 1 is also reduced. Further, in the pellet position detecting method of the second conventional example, the turntable 2
-Since it is installed on the Y table 5, the structure of the pellet bonding apparatus is complicated.

The present invention has been made in view of the above circumstances, and provides a pellet position detecting method of a pellet bonding apparatus capable of improving the accuracy of detecting a pellet position without complicating the apparatus. The purpose is to do.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a pellet position detecting apparatus for a pellet bonding apparatus for detecting a position of a pellet placed on a rotary table of a pellet position correcting mechanism by a recognition device disposed above the rotary table. In the method, after the image information of one corner of the pellet is captured by the recognition device, the turntable is rotated to position another corner of the pellet in the recognition area of the recognition device, and the other corner of the pellet is recognized. It is characterized in that image information is fetched, and a state of displacement of each corner from a reference position is detected based on the image information of both corners and the respective reference image information.

[0008]

According to the pellet position detecting method of the pellet bonding apparatus of the present invention, the position of the pellet is detected by using the image information of one corner portion of the pellet and the other corner portion. Compared to the case where the position of the corner is detected to detect the position of the pellet, the accuracy of detecting the position of the pellet can be improved.

Furthermore, since the position of the pellet is detected by rotating the rotary table without moving the recognition device and without sliding the rotary table in the X and Y directions, the structure of the pellet bonding device is complicated. I will not invite you.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a pellet bonding apparatus that performs a pellet position detecting method of the pellet bonding apparatus according to the present invention. FIG. 2 is a plan view showing the turntable of FIG.

A pellet bonding apparatus 10 shown in FIG.
Refers to a number of semiconductor pellets (hereinafter simply referred to as “pellets”) 1 obtained by dicing and separating a wafer 12.
3 are taken out one by one and bonded to the island portion 17 of the lead frame 16 and include a pellet take-out mechanism 18, a pellet position correcting mechanism 19, and a bonding mechanism 20.

Here, the wafer 12 is supported by an annular wafer ring 15 via an adhesive sheet 14, and is set as a wafer ring unit 11 on a wafer stage 21 of a pellet extracting mechanism 18. The wafer 12 has a notch 22 for checking the direction of the wafer 12.

The pellet extracting mechanism 18 includes a wafer stage 21 on which the wafer ring unit 11 is installed, and a pellet transfer 23 for extracting the pellets 13. The wafer stage 21 includes the wafering unit 1
1 and the wafering unit 11
The gap between the pellets 13 is enlarged by stretching the pressure-sensitive adhesive sheet 14 to facilitate the removal of the pellets 13 by the pellet transfer 23. The pellet transfer 23 has a suction nozzle at the tip, and the pellet 1 pushed up from below by a push-up pin (not shown) if necessary.
Then, the pellet 13 is placed on the rotary table 24 of the pellet position correcting mechanism 19.

As shown in FIG. 1, the pellet position correcting mechanism 19 includes a rotary table 24 on which the pellets 13 taken out by the pellet transfer 23 are placed, and a detection device for detecting the position of the pellet 13 on the rotary table 24. And a camera 25. Pellet position correction mechanism 19
Is installed between a lead frame transport rail 26 for transporting the lead frame 16 and the wafer stage 21, and a detection camera 25 is disposed vertically above the wafer stage 21. The pellet position correcting mechanism 19 detects the position of the pellet 13 and corrects it appropriately, as described later in detail.

The bonding mechanism 20 has a bonding head 27, and a suction nozzle (commonly referred to as a collet) provided at the tip of the bonding head 27 rotates the rotary table 2.
4 is picked up and fixed to the island portion 17 of the lead frame 16 installed on the lead frame transport rail 26 using an adhesive or the like.

The rotary table 24 is configured to be rotatable in forward and reverse directions as shown in FIG. As shown in FIG. 2, the recognition area 28 by the detection camera 25 is one corner A of the pellet 13 placed on the turntable 24.
, And this is the vicinity area. Next, a method of detecting the position of the pellet 13 placed on the turntable 24 using the detection camera 25 will be described.

First, as shown in FIG. 2A, the detection camera 25 detects the pellet 13 located within the recognition area 28 thereof.
The image information of one corner section A is taken in. Next, FIG.
As shown in (B), the rotary table 24 is rotated 180 degrees without changing the position of the detection camera 25, and the other corners B of the pellet 13 are placed in the recognition area 28 of the detection camera 25.
And captures the corner B image information. The other corner portion B is a corner portion at a diagonal position with respect to one corner portion A. The image information of the two corner sections A and B captured as described above is respectively processed by the image processing section.
Value processing (or multi-value processing) is performed. Then, a preset feature image (reference image information) is found from the binarized (or multi-valued) image that has been subjected to the image processing by using a pattern matching method or the like, thereby finding the X, Y, and θ directions below. Is detected, the amount of displacement of each of the corner portions A and B from the reference position and the displacement state such as the direction of displacement are detected. Then, the reference position of the characteristic image and each corner portion A with respect to this reference position,
The position coordinates of each of the corners A and B are obtained by calculation from the position shift state of B, and the position of the pellet 13 is detected.
Since the pattern matching method itself is known,
Detailed description is omitted.

After the misalignment of the pellet 13 in each of the X, Y, and θ directions is detected in this manner, the misalignment of the pellet 13 in the θ direction is determined by rotating the rotary table 24 as in the prior art. The position shift state in the X and Y directions is corrected by the position correction of the pickup position by the suction nozzle of the bonding head 27. As a result, the center position of the pellet is picked up by the suction nozzle and the lead frame is moved. It is transported to a predetermined position and bonded.

According to the above embodiment, since the position of the pellet 13 is detected by detecting the positions of one corner A and another corner B of the pellet 13, the first conventional example (FIG. 3A )), The position detection accuracy of the pellets 13 can be improved as compared with the case where the position of a single corner portion a is detected to detect the pellet position.

Further, the recognizing device 25 is not moved, and the rotary table is set to X, Y as in the second conventional example (FIG. 3B).
Since the position of the pellet 13 is detected by rotating the rotary table 24 without sliding in the direction, the structure of the pellet position correcting mechanism 19 does not become complicated.

As another embodiment of the above-mentioned pellet detecting method, after detecting one corner A of the pellet 13 by the detecting camera 25, as shown in FIG.
4 may be rotated by θ ° to detect the position of another corner C of the pellet 13. Other corner C
Is a corner portion adjacent to one corner portion A of the pellet 13, and the above θ represents the dimension between these corner portions A and C by the rotation angle of the turntable 24. When the pellet 13 is square, θ is 90 ° as shown in FIG. 2 (D).

[0022]

As described above, according to the method for detecting the pellet position of the pellet bonding apparatus according to the present invention, the accuracy of detecting the pellet position can be improved without complicating the apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a pellet bonding apparatus for implementing a method for detecting a pellet position in a pellet bonding apparatus according to the present invention.

FIG. 2 is a plan view showing the turntable of FIG. 1;

FIG. 3A is a plan view showing a rotary table of a pellet bonding apparatus that performs a pellet position detecting method of a first conventional example, and FIG. 3B is a pellet position of a second conventional example. It is a top view showing the turntable of the pellet bonding device which performs a detection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pellet bonding apparatus 13 Semiconductor pellet 19 Pellet position correcting mechanism 24 Rotary table 25 Detection camera 28 Recognition area of detection camera A One corner of pellet B Other corner of pellet

Claims (3)

(57) [Claims] 1. A pellet position detecting method for a pellet bonding apparatus, wherein a position of a pellet placed on a rotary table of a pellet position correcting mechanism is detected by a recognizing device disposed above the rotary table. After taking in the image information of one corner of the pellet, the rotary table is rotated to position another corner of the pellet in the recognition area of the recognition device, and the image information of the other corner is taken in, and the two corners are taken. A pellet position detecting method for a pellet bonding apparatus, comprising detecting a positional deviation state of each corner portion from a reference position based on image information of the portion and each reference image information. 2. The pellet position detecting method for a pellet bonding apparatus according to claim 1, wherein the another corner is a corner diagonally opposite to the one corner. 3. The pellet position detecting method for a pellet bonding apparatus according to claim 1, wherein said another corner is a corner adjacent to said one corner.